Two years after Mad Max: Fury Roadset a new gold standard for American action movies, Charlize Theron is back in the driver’s seat again for Atomic Blonde, a slam-bang spy picture built around her butt-kicking MI6 agent, Lorraine Broughton. Directed by David Leitch — one of the two masterminds behind the John Wick franchise — the cult summer hit delivered several next-level setpieces, including an single-take stairway battle that topped Yahoo Entertainment’s list of the 10 best fight scenes in American movies. In this exclusive behind-the-scenes video clip from the Atomic Blonde Blu-ray, which hits stores on Tuesday, Leitch provides some insight into how he and his star pulled off such a technically and physically challenging sequence, accomplishing a career goal he’s had for years in the process. (Watch the clip above.)

For obvious reasons, Leitch says he warned Theron early on that she was going to have carry the bruising weight of the stairway fight. “I told Charlize, ‘I’m going to hang this whole sequence on your shoulders,'” he remembers. “I’m not going to leave the character; we’re going to stay with it, and it’s going to be disturbing and it’s going to be emotional because we don’t cut away.” To further enhance the already painful realism, Leitch had his fight choreographer and stunt coordinator actually operating the camera instead of a separate camera operator. “They just know where to put the camera for the choreography.”